I don’t think that word means what they think it means

I am no lawyer, but as I understand preemption, it means that states can’t ban something allowed by federal law (or cities by state law, etc.); the Arizona statute does no such thing; it parrots federal law.

If the government is going to make the case that the Arizona law is superseded by the federal law that they are choosing not to enforce, I don’t think they will be successful. All that will do is draw attention to the glaring incompetence of the federal government with respect to fulfilling its obligations.

And they are obligations; the law is the law. If the law is the problem, it should be changed; merely pretending the law we have doesn’t exist (or is unenforceable) isn’t the solution.

On the other hand, perhaps this means that all states with more restrictive firearms laws than federal firearms laws are invalidated because of preemption! I don’t think the administration has any idea of what it’s doing here, and it could backfire on them in a big way (definitely if they lose, and probably even if they win).